The present invention, in some embodiments thereof, relates to dental measurements, and more particularly, but not exclusively, to a device and method for subgingival measurement.
Dental treatments often involve measurement of the patient's mouth. In particular, construction of crowns, bridges and other dental prosthetics generally involves measurement or acquisition of three dimensional model/s of existing dental structures. Often prosthetics extend below the gum line, and measurement of dental structures below the gum line is carried out. Accurate measurement/s and/or modeling can facilitate a good fit of the prosthetic constructed using the measurements/s and/or model/s to the patient's mouth.
Dental impressions are a traditional technique for providing a model of the mouth. Generally, a cast is produced from the impression and the cast then is used to produce the prosthetic. Such techniques suffer from inaccuracy due to multiple manual steps which can be technically demanding on the dentist as well as invasive and uncomfortable for the patient, especially if subgingival measurement is necessary.
More recently, digital scanning techniques have offered increased accuracy and detail of measurement. However, such techniques are only able to image, measure and model visible parts of the patient's mouth and generally do not provide imaging of subgingival areas. CT scanning can provide measurement of subgingival areas, however it does not provide soft tissue measurement.
Both existing physical impression methods and digital impression methods of measurement of subgingival areas usually include the step of physically separating the gingiva from the circumference of the tooth (or teeth) to be measured for the time that measurements are taken. This separation usually causes bleeding which needs to be stemmed or prevented before measurements can be made. The process of separation sometimes causes trauma to the gingiva, which can lead to inflammation and permanent damage to the gingiva.
One common technique for separating gingiva from the teeth for subgingival measurements is cord packing, where cord/s are inserted between the tooth/teeth and gingiva, holding the gingiva away from the tooth surface. Cord packing is generally a time consuming procedure, stressful and technically demanding for the dental practitioner and painful for the patient.
Dental practitioners may have a dilemma, either to use damaging, painful, technically challenging methods to expose subgingival tooth areas (e.g., cord packing) for measurement or to forgo subgingival measurements resulting in either ill-fitting prosthetics or prosthetics with unpleasing aesthetics where the border between the prosthetic and original tooth structure is visible above the gum line.
Additional background art includes U.S. Pat. No. 7,346,417, U.S. Pat. No. 5,257,184, U.S. Pat. No. 5,320,462, U.S. Pat. No. 7,625,335, U.S. Patent Application Publication No. US2008261165, U.S. Pat. No. 7,813,591, FR2692773, U.S. Pat. No. 5,224,049, U.S. Pat. No. 5,372,502, U.S. Pat. No. 7,494,338.